Four in custody after pursuit in south west Sydney

Four people are in police custody following a pursuit from Merrylands to the Illawarra and back to Campbelltown this morning.

The initial report was made about 3.50am today, when a silver sedan was being followed on Richmond Street, Merrylands.

The pursuit continued through Smithfield, Liverpool, and Campbelltown before being terminated by police at Broughton Pass Appin.

About 40 minutes later, a Dog Squad officer sighted the vehicle and followed it before another pursuit was initiated in North Wollongong, where the silver Nissan Pulsar turned around and headed north.

The pursuit ended in Woolmers Place at Glen Alpine about 5am when the sedan was trapped in the cul de sac by the police vehicle.

Police allege the police vehicle was rammed by the sedan.

Three people were arrested at the scene and a fourth was arrested after being tracked to a street nearby by a police dog unit.

All four have been taken to Campbelltown Police Station.

A police officer has been taken to hospital to be checked for a possible knee injury.